ERA by Temperature

Below are data visualizations that present how a Major League Baseball player's Earned Runs Average (ERA) is impacted by the temperature in the 2021 season.

ERA is a statistic in baseball that represents how many runs a baseball player is giving up on average per 9 innings. In baseball, runs are used to determine the winner of each game. The team that scores more runs wins. For this reason, a better pitcher has a lower ERA, as they are allowing the opposite team to score fewer runs. ERA is therefore a measurement of how good a pitcher is. The lower the ERA, the better.

We'll first look at how Max Scherzer, an MLB player currently on the New York Mets, was impacted by the temperature in of games in 2021.

It is difficult to draw conclusions of Max Scherzer's performance in 2021 based on this circle area chart alone, given the small sample size of games that each temperature range covers. Nonetheless, there are some interesting points to take away from this data visualization.

The first point to take away is that Max Scherzer seemed to perform at his worst when the temperature was between 59 and 66 degrees. His ERA is games with that temperature was 5.40. The circle labeled with "Between 59 and 66 degrees" is larger than all of the others, indicating a higher ERA.

The second point to take away is that Scherzer seemed to be at his best when the temperature was below 59 degrees. His ERA in those games was 1.04. The circle labeled "Less than 59 degrees" is smaller than all of the other circles, indicating the lowest ERA.

Despite these points however, it is difficult to establish a strong correlation between Scherzer's performance and the temperature, given that his ERA varies significantly for each temperature range.

Now we'll look at how Luis Castillo, a pitcher on the Cincinnati Reds, was impacted by the temperature in 2021.

The immediate takeaways from the data visualization above is that Castillo's ERA seems to be a lot higher when the temperature is cooler. When the temperature is between 59 and 66, his ERA is 8.140. His ERA is also high in games when the temperature was between 59 and 66 degrees, being at 4.910. For the range of 67 and 73 degrees, his ERA was 4.85.

Castillo's sweet spot in terms of performance seemed to be when the temperature was not too hot and not too cold. When the temperature was between 74 and 79 degrees, his ERA was 1.80! In the range from 80 to 86 degrees, his ERA was 2.75.

Unfortunately, Castillo's ERA skyrockets to 6.26 when the temperature is above 86 degrees. Despite the small sample size of games for this temperature range, this might indicate that Castillo's performance is worse in games where the weather is very hot.